I heard this music a lot of times and I always loved it! Whenever I asked me why, the answer was that the musical ideas are not so new, not so original (the Penguin's and Selina's themes are musically quite banal), but so well adherent to the situation, and so well orchestrated that they have a strong power.
For example, the beginning idea of the penguin has a so dark orchestral colour with the chorus, with the organ that you forget that is a quite volgar round dance. And in the same time, it has a perfect adherence to the developping of the action that is astonishing. For example the illuminating of the harmonies and of the orchestral colour when the Cobblepots meet another couple, wishing a Merry Christmas, shows at what degree there's adherence.
Also the transformation music for Selina has a great power not for his musical means which are a chromatic descending scale on the bass, and a figuration quite usual in the highest part, but for his dryness, for his harsh orchestration and also again adherence. See how the explosions of the timpanis and the knocking the frying-pan against the wall coincide perfectly.

So the the richness of this score is not in his simple means, but in how these are used.
The last example: see with how sadness, in the end, the Selina's theme is reprised when Bruce Wayne finds the cat in the lane and comes back to his car while it's snowing all around him, in this dark, sad, gothic Gotham City!!!